Can a judge refuse to hear your filed motion to modify support?

Sure. If its not filed properly or if the motion is without merit or if its too soon since the last court action.

What was the reason given.

Agreed, you either did not file it properly, or there was not enough supporting documents to prove that things have changed. Did you prove a major change income. How long was it since the order was issued, or the last modification. I know in my child support case, unless it was an extreme income change, we were not to file for 3 years.

And if I filed, I would have had to include douments showing that things had changed or why

Your question got cut off. What did you mean to write after "... and said th"?

How long had it been since the last time support was a question before the courts and were there circumstances that drastically change since ?